1. Field of the Invention
This invention relates, generally, to the fabrication of microlenses attached to the end of optical fibers or small cylindrical rods in general. The purpose of the microlens is to focus light entering or leaving the fiber or mini-rod.
2. Description of the Prior Art
Lenses are used in fiber optics for coupling a signal propagating through an optical fiber into preselected photonic components. An optical beam exiting a fiber must be focused or collimated to facilitate its coupling to a preselected photonic component.
External lenses, one of which is known as the GRIN lens, are in current use.
Attempts, with varying degrees of success, have been made to improve upon such external lenses by positioning a lensing element at the distal end of the fiber, in the near field of the fiber aperture. However such a lens, at best, can only focus the output beam. Moreover, such lenses would be expensive to produce on a commercial scale.
One prior art lens provides a non-focusing lens in the far field; the divergence of the beam is merely reduced.
What is needed, then, is an inexpensive means for better focusing or collimating a light beam exiting an optical fiber. More particularly, a focusing lenslet is needed at the distal end of an optical fiber in the far field of the fiber aperture.
However, in view of the prior art considered as a whole at the time the present invention was made, it was not obvious to those of ordinary skill in the pertinent art how the identified need could be fulfilled.